Neurology

Neurology Upper Motor Lesions Vascular Diseases -> Stroke or TIA Basics Thrombosis, embolism or haemorrhage in specific vascular territories Deficit is usually progressive and occurs over a period of minutes. BUT continuing deterioration may occur over hours or days as a result of edema or haemorrhage around or into infarct. TIA is an episode of focal neurological disturbance attributable to a transient vascular occlusion without evidence of stroke on imaging. Physical Examination Findings ACA Leg primarily affected Anterior communicating artery Connects right and left internal carotid artery Internal carotid and MCA Dysphagia Non-dominant hemisphere dysfunction Posterior communicating artery Field cut -> supplies occipital lobe -> visual disturbances? Basilar artery Occlusion results in quadriplegia and death unless there are good anterior collaterals. Penetrating branches of the basilar artery to the brainstem. Small brainstem infarcts and often class lacunes Anterior inferior cerebellar artery Ataxia Nystagmus Posterior inferior cerebellar artery Lateral medullary syndrome Usually secondary to occlusion of the vertebral artery from which it arises. Multiple Sclerosis Constitutional symptoms: Fatigue Headache Optic neuritis Usually unilateral Painful eye movements Abnormal eye movements Can be painful Impaired vision Colour blindness Relative afferent pupillary defect Demyelination of the spinal tracts: DCLM: Decreased proprioception Decreased vibrations Decreased fine and discriminative touch Corticospinal tract -> UML Weakness Hyperreflexia Hypertonia Babinski sign -> dorsiflexion ALST Decreased pain Decreased temperature Decreased crude touch Decreased pressure sensation Thoracic and Sacral SC Urinary incontinence Faecal incontinence Ventral spinal cerebral tract and dorsal spinal cerebella tract Decrease proprioception to cerebellum -> decrease coordination -> ataxia Charcot’s triad -> part of cerebellar involvement Intention tremors Nystagmus Dysarthria -> scanning speech Cerebella involvement -> other features Poor postural control Imbalance Gait dysfunction Changes in mental state CN palsies Diplopia Facial palsy Trigeminal neuralgia (can be bilateral, but usually unilateral) Bilateral TN -> raises concern for MS especially in younger patients. Uhthoff Phenomenon A reversible exacerbation of neurological symptoms following an increase in body temperature. For example: Physical exertion Warm bath Fever Upper Motor Neuron Lesions Disuse muscle atrophy Spastic paralysis Hypertonia Hyperreflexia Babinski’s sign positive Decreased inhibition of dorsi flexors -> dorsi flexors activity overcomes the activity of plantar flexors -> big toe dorsiflexes. Pronator drift positive Damage supinator activity -> increased pronator activity. Hoffman’s sign positive Flick middle finger -> thumb and index finger come together. Lower Motor Neuron Lesions Denervation muscle atrophy Fasciculations Flaccid paralysis Hypotonia Hyporeflexia Fibrillations Peripheral Neuropathy Loss of sensations Symmetrical or asymmetrical Glove and stocking pattern. Loss of motor function Occasionally may occur without sensory changes Muscle weakness. Reflexes Reduced but may not be absent in the distal parts of the limbs. Neuropathic pain Guillain Barre Syndrome Onset is acute or subacute and symptoms progress rapidly. Symptoms peak at 2-4 weeks and then plateau over months or years followed by partial or complete resolution. Limb involvement: Progressive flaccid paresis or paralysis Paraesthesia: stocking and gloving distribution. Hyporeflexia or areflexia -> typically begins in the lower limbs. Back and limb pain: Often an early symptom Involves nociceptive and neuropathic pain Autonomic dysfunction: Cardiac arrythmias Blood pressure fluctuations -> wide variations of greater than 85 mmHg may occur. Respiratory muscle involvement: May lead to respiratory failure. Cranial nerve involvement: Facial diplegia: due to bilateral facial nerve involvement. Bulbar dysfunction. Thickened Peripheral Nerves Palpate for nerve thickness Median nerve at the wrist Ulnar nerve at the elbow Common peroneal nerve at the head of the fibula If the nerves are thickened, consider: Acromegaly Amyloidosis Chronic inflammatory demyelination polyradiculoneuropathy Leprosy Spinal Cord Lesions Anterior Horn Lesions: LMN affected -> fasciculations. LMN affected -> hypotonia and hyporeflexia. Central Cord Lesions: CST damage to central and thoracic portions: Upper limb affected more than the lower limb. UMN and CST damage -> decreased inhibition of the inhibitory medially retinospinal muscle -> increased alpha and gamma motor neuron stimulation -< increase intrafusal stimulation -> hyperreflexia. Babinski sign Collateral branches cannot go below site of injury. In all of these the damage is bilateral. Posterior Cord Lesions: DCLM damage: Decreased proprioception -> decreased cortex and cerebellum conduction -> coordination loss and walk with a wide base gait. Decreased vibrations. Decreased fine touch Decreased discrimination touch Damage is bilateral Anterior Cord Lesions: CST damage: Hypertonia Hyper-reflexia Spastic paralysis ALST damage Loss of temperature sensation Loss of crude touch sensations Loss of pain sensations Anterior grey horn damage: Bilateral LMN damage Impairment of ANS to GIT and bladder -> increases PSNS activity and decreased SNS activity: Faecal incontinence Urinary incontinence Brown Sequard Syndrome: Damage to half of the SC Counter lateral loss of sensations -> DCLM and ALST Counter lateral loss of LMNL at lesion level Complete loss Myasthenia Gravis Normal deep tendon reflexes Limb weakness Usually symmetrical Eyebrow of the unaffected eye is usually lower than the affected eyebrow. Ice pack test: An ice pack is placed on the affected eyelid for 5 minutes to improve ptosis by greater than or equal to 2 mm. Curtain sign: Lifting the more ptotic eyelid worsens ptosis in the contralateral eye lid -> eyebrow elevation and furrowing of the forehead can also occur. Cogan lid twitch sign: Brief eyelid twitching when looking straight ahead after 10 to 20 seconds of downward gaze. Simpson test: Use to reproduce eyelid fatigue -> positive if looking upward for more than 1 minute (without lifting the head) provokes eyelid fatigue.